(1) Field of the Invention
The present invention relates to an agent for accelerating the maturation of field and garden crops from which fruits, seeds, roots or subterranean stems are harvested. The present invention also relates to a method for accelerating the maturation of field and garden crops from which fruits, seeds, roots or subterranean stems are harvested.
(2) Description of the Prior Art
There is considerable interest among cultivators of field and garden crops in the early harvesting of the crops, the increasing the crop yields and the improvement of crops qualities, such as sugar content, acidity, color, starch content and protein content.
Heretofore, in order to accelerate the maturation of fruit trees and fruit vegetables, the surfaces of leaves and fruits of fruit trees and fruit vegetables were sprayed with or the harvested fruits were fumigated with substances having a respiration poisoning effect, such as lead arsenate, gaseous hydrocyanic acid and the like. Although such spraying and fumigating are effective, there were problems in these methods in that prematured fruits not having good quality were occasionally obtained and the growth of the fruits is stopped due to the fact that the physiology of the plants are changed by the use of said substances, and also, that a slight amount of arsenic or hydrocyanic acid, which is toxic, is likely to remain in the fruits.
In order to accelerate the maturation of field and garden crops, it is also known that the surfaces of leaves and fruits of plants are sprayed with lime sulfur or the mixture of phosfate solution therewith. However, this method has a problem in that, since the white powders of the above-mentioned agents are adhered to, for example, the surface of the fruits after the treatment, the market value thereof are decreased.
Furthermore, the market value of citrus fruits, such as tangerines (or Unshu mandarin oranges), navel oranges and Iyo oranges, is influenced by the size, shape, color and sweetness thereof. Among these, the sweetness is most important for the market value of citrus fruits. It is known that the sweetness of the citrus fruit mainly depends on the sugar content of the fruit and, in turn, the sugar content increases with an increase in the content of carotinoid type pigments contained in the epidermis of the fruits (i.e. with the increase in redness of the epidermis). Thus, the degree of redness of the epidermis of citrus fruits is an important factor which determines the market value thereof. It is, therefore, desired that the early harvesting of citrus fruits and the early coloring of citrus fruits can be simultaneously achieved.